Surgery as pluripotent instrument for metabolic disease. What are the mechanisms

Bariatric metabolic surgery currently offers the most effective treatment to achieve sustained weight loss and improvement in metabolic comorbidities, such as type 2 diabetes, hypertension, dyslipidemia and cardiovascular diseases. The number of cases performed in Germany and also worldwide is continuously increasing but the underlying mechanisms of bariatric metabolic surgery are still not completely elucidated. Roux-en-Y gastric bypass (RYGB) surgery represents one of the most commonly used and therefore most frequently investigated bariatric metabolic procedures. Traditionally, its effectiveness was attributed to food restriction and malabsorption but in the meantime it has become evident that the underlying postoperative mechanisms of RYGB seem to be much more complex. Potential mechanisms include multiple physiological changes, such as altered levels of gastrointestinal hormones, increased energy expenditure and modified gut microbiota as well as many other factors. This review article therefore aims to offer an up to date overview of relevant mechanisms that improve obesity and its associated comorbidities after RYGB surgery.